Automatic steering device



Feb. 15, 1944. w. MLLER ETAL 2,341,544

AUTOMATIC STEERING DEVICE Filed March 29, 1940 NvENToRs New),

STERREN@ MEVE Mollet?, vilneciliivZehlvmdorif, and Adame iioueuberger, Berlin f Halensee, Germany; vested isn the Alien Property Custodian liooiicetion lisrch 29, 194i), Serial No. 326,648 is Germeey December 12, 1938 (Cio 24M-318) n 4 cams.

The invention refers, senese-i, to automatic M .ivangemeuts te; which is also meent, in

tice so-celled regulates enormemente. s is intended especleii "os :application to auf tomzmtic ccltroi of electa With automatic steering arz'ericements for alim planes, engelse speed and iti some cases also arl-s e'ulalf acceleration as weil as eventual urthei' coutcol values solde from the coeti'ol necessitated *y pleries dying position, ete impressed on the societ To ettsin e 'ceect steering; eoctei sctioc. the various control impulses must ce timed to ecole ctlxers magnitude.

To facilitate the coreet, reciprocal measure ci 'tile impulses, it iles elread'y been suse gested to icciude a spring between the control tra'csmitter and the powet switch for the servo unit. 'liaousli the choice of springs of various stlness, the triueuce of the individual control trensmttte oo the power switch can be changed irl c. simple meesten Trie present toveution distinguishes itself from 'tice aforementioned sri'aogements in that tite resilient, sptimes] connection between the control ti'cosmitter cud the power switch is so malutzuned under initial tension that the spring yields only site? the passing of the highest control val des end limits same, in case of further deectlou g to e. constant value.

er, a limitotioti of the eoxotsoi desired magnitude is ,occstole Witheet the sensitivity of the control treesM @u time other houd, e strict lineas" de lsetvveeo the signal departure and the 35a. of 'line indicating the stee'siug direction is used since the generally' strongly datteried die veeseoce ci" oaremete ect trol velues fortifier ce mad 1 distant lr s wes, in eenersl, not

or 'tl some l e et, el etiei'lsicc of the i Figs. 2 and 3 show two further forms of the spring or yielding connection under initial tension.

fi is a diagram illustrating the principle involved.

in Fig'. l, i8 indicates an eccentric control disc fastened to axis li which axis is controlled, for example, by a. magnet needle I2, s directional gyro or any other position maintaining or measuring device adapted for impulse generation. The compressed air, tiowiug in direction of arrow i3, hits the two orifices il and l5 unequally according to the position of the control disc Il), whereby e. diflereruzlal pressure is created in lines li, l1. Sadlines lead to the two sides of housing I8 which encloses the control diaphragm i9, and to the housing of the pneumatically operated course indicator or telemetrc compass i9', the motion of which is caused by e pressure sensitive measuring' system, not shown but in parallel to dlacliragm i9. For a further description of this type of pick-off and e'mote reading compass see the prior patent to Wunsch No. 1,729,850, dated October ll, 1929, for Steering indicators for aircraft.

The movements of diaphragm i9 are transmltted by pin 20 and lever 22, moving around fulcrum 2l, through linkage 23 and 24 to jet pipe power switch 25, movable around axis 26 which is vertical the clame of the peper. Compressed sir oi: :duid under pressure is ecl into the jet pipe its the divectlon of the afow 2l. Wheeby a dtferential pressure acting on the piston 30 of the servo 3i is cveated by the position of the iet pipe in iront of the two dividing openings 28. 29, resulting in the ielative displacement of the 'udder 32. By means of two centalizing springs 33, 34 the jet oigse is nomcally kept in its central position. its movement is limited by stops 35, 36.

right end oi lever 22 is foribshaped. On eac-l1 of the two level" ends ll, 38 is a piece 39, 4U conical shape on the outside and cylindrical on the inside. Both mitts ere movable on bolt H which is etteclietl to 'ein '29. Helical spring 50 presses with a @estais tension the two pieces 38 end il@ ege/.inst levee 3i', 38 end against the sct'eivs ii, zfespectively, which rest ou the end o boit i i. Screws so set that the trans i 2li tolever 22 taires without e .y lost motion. .As ione es s t'fensmtted 'from diem pi'lregro iti to pin 2t .A -d to lever 22 is less than tile spring tension, the diaphragm motion is ezt and rigidly transmitted to the iet pipe. However, the power necessary to displace the jet pipe attains higher values, for example' if the centralizing power of springs 33, 34 overpowers theltension of spring 50 or the jet pipe hits against the stops, the spring will then yield and, according to the direction of motion of pin 20, conical piece 39 or 4B is taken along by nut 42 or by nut 43, respectively, and lifted from its respective seat. Diaphragm I 9 can therefore continue to move without moving lever 22. The spring is so designed that its change of length has no material effect on its initial tension. The transmitted turning moment after the lifting oil of one of the conical pieces 39, MI remains practically constant.

'I'he arrangement makes it also possible for the jet pipe to carry out any possible movements inside its stops 35, 36, regardless of the position of diaphragm I9. These movements are derived from the other measuring device such as, for example, a gyro 60 with two degrees of freedom measuring the turning speed of an airplane. For example, when starting a turn by displacing stationary parts Id, I5 of the control transmitter of an automatic steering arrangement, the springy, resilient connection transmits only a fraction of the differential pressure of diaphragm I9 to lever 22 and thus to .let pipe 25. The precession of the rate of turn gyro 60, due to the turning of the plane, exerts an opposing moment on the jet pipe through link GI and, through the balancing of both impulses, the jet pipe takes a position such that the rudder receives the necessary deecf tion for the desired rate of turn.

The turning moment 'transmitted by dlaphragm I9 to jet pipe 25 is limited by the initial tension of spring 50. However, the higher control values are indicated by the course indicator I 9' whose sensitivity is attuned to the impulse transmitter I U-I 5.

Fig. 2 shows a very similar method of resilient connection held under initialtension. Instead of the bolt 4I piercing the conical pieces 39, 40, there is a fork-like part 4I whose ends 42' and 43 rest against the parts 39 and 40 in a manner similar to that of screws 42 and 43 in Fig. l.

In the arrangement of Fig. 3, the pin 20 carries a fork 4I" between whose ends rests pin 44 perpendicular to the plane of the paper. On lever 22', at 45, two levers d6 and 4l are arranged to swing, though normally they lie close to lever 22 under the tension of spring 50. The levers 22', 48 and'l move together until spring 50 yields, after passing its initial tension, whereby only one of the two levers 46,- 41 on lever 22 remains closed while the other one moves away.l

It was shown above that the lengthening of spring 50, due to its yielding, should not result in a marked increase of spring tension. For most cases this demand can be metthrough the choice of a spring which, unsprung, is dennitely longer in Figs. 1 and 2, on shorter in Fig. 3, than under initial tension in operating position. How ever, ii the greatest possible impulse exceeds the control value limit by considerable, and if a very accurate maintenance of the transmitted turning moment is desired, limit stops 48, 49, limiting the stroke of the diaphragm, may be supplied and so set that the motion of lever 22' sumces to move the connected power switch to its two terminal positions.

In Fig. 4, the line indicating the steering direction of the impulse transmitter Ill to i5 is shown to indicate the edect so gained. The differential pressure acts on diaphragm I9 due to its dependence on the course deviation. At points Pi and Pi'. respectively, spring l0 begins to yield so that the iorcetransferred to fork 22 takes the course indicated by the dash lines. The still remaining, slowly growing control value transferred to the power switch originates from the increased tension of spring due to the great diaphragm stroke. If, now, limit stops 48, 48 are added, the curve breaks a second time at points Pz and P2' and from there on takes a horizontal course, as shown by the dotted line. As shown by the pro- `iection of points Pi (Pi') and P2 (Pa) on the abscissa and ordinates, the increase of the transferred moments after the rst break of the line indicating the steering direction at points P1 and Pi' is very small, but is greatly exaggerated in the pictorial representation. In practice points P1 and P2 would be permitted to merge, which is permissible because the diaphragm stroke reaching to point Pi, the jet pipe must have reached its position against the stop ii' no reaction has acted on the centralizing springs 33, 34; otherwise the deflection would be insuilcient. Y

In place of the pneumatic impulse transmitter system I0-I 5. any other desirable measuring system may be used, and jet pipe 25 may also be replaced with another power controller or relay.

What is claimed is:

1. In an automatic steering arrangement for aircraft having a course deviation measuring means, a differential pressure responsive device controlled by said measuring means and a steer-` ing control means; a two part linkage for normally directly transmitting the eiort exerted by the did'erential pressure responsive device to said steering control means, said linkage including a normally unyielding spring controlled connection for the respective parts thereof, the spring of said connection being adapted to yield only when the eort of the dierential pressure device exceeds predetermined limits, such excess effort being absorbed by the spring so the same is not transmitted by the linkage to the steering contro means.

2. In an automatic steering arrangement for aircraft having a course deviation measuring means, -a diierential pressure responsive device controlled by said measuring means and a steering control means; a two-part linkage for normally directly transmitting the effort exerted by the differential pressure responsive device to said steering control means, said linkage comprising a two-part hinged or forked lever, a pin therebetween connected to said device, a link also therebetween adapted to control said steering device, and a spring yieldingly holding the two parts of said lever against the two sides of said link and pin, whereby said link moves with said pin except when the pressure exerted by said device exceeds the spring tension.

3. In an automatic steering 'arrangement for aircraft having a course deviation measuring means, a diierential pressure responsive device controlled by said measuring means and a steering control means; a two-part linkage for normally directly transmitting the eiort exerted by the differential pressure responsive device to said steering control means, said linkage comprising a lever having a C-shaped end, a pair of one-way slip connections for transmitting the movements of said device to said lever, one for each direction, and a compression spring for preventing slip of both connections until the spring force is exceeded.

4. In an automatic steering device for aircraft and the like having a position maintaining means.

erted by the differential pressure responsive de vice to balance both impulses, said linkage including a normally unyielding spring controlled connection for the respective parts thereof, the

5 spring of said connection being adapted to yield only when the effort of the differential pressure device exceeds predetermined limits, such excess eiort being absorbed by the spring so the same is not transmitted by the linkage to the power 10 switch.

WALDEMAR MLLER. ADAM KRONENBERGER 

